Abstract: Decomposition-coordination methodologies for the optimal reliability design of a whole mechanical system are developed according to the decomposition-coordination principle of the large system theory. The solve process of the optimal reliability design of a whole mechanical system is transformed the iterative process of the optimal reliability design of elements in the system. The approaches can overcome "dimension disaster" caused by the large-scale model of the optimal reliability design to a whole mechanical system, as well as make full use of the achievements in the optimal reliability design of mechanical elements. Numerical examples are provided to illustrate the effectiveness of the methods.

Key words: Decomposition-coordination, Mechanical system, Optimal design, Reliability